I have to make a little clever remark here!
To some extent this is a pseudo-question. Zhao Mengfu’s Huangting Jing — every single character in it is so beautiful it breaks your heart.
But since you insisted it must be limited to seven characters,
there’s only one choice!
“中华人民共和国！” (People’s Republic of China)
Exactly seven Chinese characters 🙂
This one was written by Chairman Mao:
This one was written by Qi Gong — he was the last direct descendant of the Qing imperial household, but also the last “traditional” calligrapher:
This one was written by a woman. Although she learned Ouyang Xun’s cold, severe, and forbidding brushwork, these particular characters are written in a very coquettish way, full of feminine grace:
…
Calligraphy as an art form is a little strange: outside China, Japan, Korea and Vietnam it’s basically nonexistent — unlike Go, for example, which has a fair number of players in the West, some quite strong.
In terms of skill, China is absolutely in the lead.
Korea has done well with revivalist approaches.
Japan is weird: when I look at their kanji and katakana calligraphy sometimes I feel, “How could this be shown in public? （too bad,I mean）” — but their hiragana calligraphy (similar to Chinese cursive script) is extremely strong!
Very interesting.
I know little about Vietnam — it’s competent and by-the-book.
But being by-the-book has its merits: at least it doesn’t make mistakes.
Japan does have some original ideas.
If you watch a lot of old Japanese films you’ll notice the font used for the opening credits — it has a distinctive flavor.
(The opening credits of Seven Samurai)
It’s clearly Tang-dynasty regular script, in the Yan style.
But!
If you look closely you can see it blends in the spirit of the Wei stele style!
That gives it a peculiar savor — a flavor China itself didn’t invent.
In that respect, Korea and Vietnam are a bit less innovative than Japan.